Electric induction furnace



May 15, 1923.

A. E. GREENE ELECTRI C I NDUCTI ON FURNACE Filed Feb. 24, 1920 m Ms\ `invention avoids this clitlicnltv .tion furnace en'l vet vvlrereloy tliese resn ,s

Petentedl Moy lll, w23.,

lSSflrlli FFlCE,

ALBERT lll. GREENE, @E SEATTLE, WSENGTN.

Application filed February 34, 192?. Seidel No. Sl.

T 0 all whom it may concern:

Be it known that l, ALBERT E. Gnnnnn,

`citizen of the United States, residing et Seattle, in the county of and State o? Washington, lieve invented e certain nenT and useful lmprovement in Electric lndnction llurnces, of which the ollovvina is o specification. l Y

My present invention reletes to the struction and operation ol inilnction neces. Y

@ne object of my invention is to provicle means ol' passing o large current through e channel containing molten metal et the saine time prevent the i'netel from contrecting due to the effect of excessive current, or :1t-any rote to prevent tlie molten metal current. There is n dilicnlty' in the operation 'o5 an induction furnace lnovv'n as the pinch elect it may described as the effect o-' excessive current on the molten metal tenclingy to ineke tlfie nietel contract esserne smaller cross section and loreelr tlie clrcnit` lli/ly sent discovered tlict the pinch enec; rn Ace minimized or evoicle oy increasin@q the static pressure on the the incluetion channels.

@ne advantage of rey l. om nlole to force e l through e smell cross section o'l and in 'lierefore able to use -e smell sized furnace in vvliicli tlie lines or rce inode more elliciently to encircle lootli 'o cry seconclery circuits anal tlicre'ore u le to rise c high energy input emi yet reletively high power lectore lll/l" invention contemplates novel constructionot' induction furnace vf'liereliy ncreosecl omver may ce uselL enel creat er ergy developed Within et molten conducto stitnting7 the secondary circuit conluri tion is may ne accomplished wit-"n relatively liign povver lector. A. disadvantage of en duction furnace of large con ci y flore lios been itsl lovv power l necessity ol correcting the `lect lay low frequency cnrre means., This disadvantage res from the considerable distance innry end secondary circuits encli the core and the seconrlerv. my p ent invention, however, l

-vvith metal cete the primary in close proximity to tlie secondary and ein also .able to locate tlie core with relation to the circuits so that there is reletively smell amount of lei-rlinge lnn that (loes not encircle both cirt@ cuits.

@ne feature olf my invention relates to the constrnctioi oil tlle furnace sliell whereby e relatively liigli lieerl ol metal is proviclecl to cause increased pressure on tlie vmetal l tlie cliennels.. y

@ne 'lecture ol niy invention lios to lo with the construc'f' n ol' tliernegnetic core whereby tlie core con prises port ol the furnace sliell or serves es a container for the reirac'l y lining, 4

Another feature relates to tlie construction the channels, endl other'ieetnrss relete tothe primary windings, their constrnction,n tlie rnetliorl controlling tlie energy development of the furnace :incl other tures vfnicli Will more carefully olescriloecl liereinelten is plan view of tlle el enel lli@ lli on l 'i l o ,n i.. s en eno vienT 1n elevation or Fig; 5, C? .is o sectional elevation nnotn` moonncetion ol2 roy invention. Fi

tnis furnace enel ig. 4 n en along line All of Fig.

erence l; tlie primo-ry eliovvn et l end the cliennel lllerl n et 2 enel erouncl the channel rerrnctory lining E, ne refractory lining; materiel lield in 'the-'furnace frame shell in this inoclil ition of my inven-- tion the magnetic core enel 5 serve to conm ing. These megnetic cores motie up "all t le sl'iows one o c pien vievv of Sectio ll? i ivincling is mi' l g/uy i cooled copper Wound round 'elle iney ce lli-teen turns to one cor*l it ll@ Sir connected to il() volts. in. onder noioeaie the coii close to the secondary have used Water cooling aneihave als@ provided en insulating partition 7 above the primary Winding and between ik; and the seeendai'y. The primary may be Wound around Mie side ie s of the cores either 011 the inside ei the secondary or on both inside and outside or on any er on all fsicies of the Seconde-ny. .i may aiso'insert a metal strip 8 ef hiess for example between the 'm70 cireuits te pnotect 'bhe pi'imery from injury from molten metal. 7fiie refractory channel consiss of suitable meceiai fof holding; eine moiten metal. It may be mede of siiieeJ mixed with ele-y or @they minding materiei, and if desired this .mixture may contain @iso carbonio ineke 'fee Whoie more refineiory; onv it may be Joie iarggeiy of megnesite or meg'nesite 7ned with eei'bonaceeue maeilaL @inside i'efmet'oiy and between ifa and ne inieeesnel er at any i ouiside if' the reinem/Ory, l preferabiy piece hens, insulating maieiizii es shown at 9; this seives to keep the iieei'iargeiy in tile inoien metal enito preieabiy ineke ine Sniensions 'fnineee smaii se 'haz the We eirenits e :inches- .iiz and eine :bien of eei'e ieneineing' the en, 'winding ine meg eeie yoi |Tes eompieie ine inf nl t G ,ioni smnnpolnteensiiuetien and op "ie efieeieiy enn eiieiency and eos@ :nnen enciose wipes: azie hewn SS D18 j et noie,

ini.

nennen pus evei from ehe eignen sicie of the furnace. Or le metal me* be heated and then. she furneee tapped oni, iem one of the lower tap .holes as at i8; en the furnace may be ilteci o: ery ci n' se as te heat the i. Veiy rapldly., Thus ny be iie 'mib furnace :ino in nciuetion furnace e; very is net, the desired incise The pipes are assume om the ipes for inne siieil as already described or in any suitable manner. The current may be kept on while the furnace is in horizontal position and the current controlled so as not to cause excessive current to flow. The pipes 19 and 20 may be made as long as desired. Metal may be poured into the furnace through the pipe 19, thevmetal may be heated as much as desired and then the furnace may be tilted and the metal poured out either all at once or a ladle full at a time.

The channels in these pipes 1, 2, 3, and 4 of Figs. 4 and 5 may be made in any suit- .able way, for example by ramming the re' fractory material around cores or forms which may subsequently be withdrawn and the lining of the pipe dried and then inserted in place in the furnace. When assembling the pipes together, suitable mixture of refractory may be placed between the pipes and then they are bolted together to make a good joint suitable for retaining the metal.

The furnace 'of Figs. 7 and 8 show a further modification of construction.

This furnace construction of Figs. 7 and 8 shows the method of placing the lining and cores both inside a suitable container or shell. This container may be made of brick with or without a metal shell. rll`he cores are shown at 1, 2 and 3 in Fig. 8 and in Fig. 7 a top yoke 4 covers the tops of the cores. n Fig. 7 windings are shown diagrammatically at 5 encircling core leg 1, at 6 encircling core leg 2, at 7 encircling leg 3, at 8 and 9 encircling the portions joining the legs 3 and 2 and 2 and 1, respectively.. and also at 10 encircling the center leg 2. These all maybe water cooled if desired so as to maintain low temperatures in the cores. Channels 11, 12 and 13 are shown. The center channel 11 may be used alone if desired in which case the furnace will operate as a single phase furnace; or the other channels 12 and 13 may be used also in which case the furnace may be operated three phase if desired, one phase for each channel. rllhe static pressure may be maintained by filling the furnace to the desired level or by using pressure pipes as already described. When operating single phase the windings may all be used or any one of them only and they may be operated in series or in parallel. 'll`hc use of the coils in series or parallel may be for the purpose of varying the number of turns connected to the supply circuit so as to control the power in the furnace all as described in my U. S. Patent No. 1036996 and my application for patent, Srfhlo. 740,034. filed Jan. 3, 1913.

The shape of channel may be made as desired either wide and shallow, or narrow and deep or round or square. A tapping spout 15 is shown in Fig. 8.

What I claim is;

1. An electric induction furnace comincreased head of metal may be maintained on the metal in the endless channel while heating the metal therein.

2. An electric induction furnace comprising a primary winding, an endless channel in refractory material and adapted to lie in an approximately horizontal plane for receiving a comparatively small amount of molten metal to form a secondary circuit, and a channel in refractory material communicating with said first-named channel and leading upwardly to contain molten metal'and form a head to increase the static pressure on the molten metal in the secondary circuit.

3. An induction furnace for electrically heating molten metal. comprising an endless channel in refractory material, and an auxiliary channel in refractoryl material communicating with said first-named channel and of small cross-,sectional area but sufficient to permit free flow of the molten metal into said first-named channel and another auxiliary channel out of which second channel the metal may leave the furnace, the outlet of said second auxiliary channel being adapted to maintain an increased metal static pressure on the metal in the endless channel while induction heating thereof proceeds.

4. ylllhe method of relining`metal in an electric furnace which consists in inducing a large electric current through a small.

volume of metal in a secondary circuit lying l in an approximately horizontalplane, and exerting pressure on the molten metal in the said secondary circuit by producing a head with molten metal leading upwardly through an auxiliary channel communicating with said first-named channel.

5. The method of treating metal in an electric furnace which consists in inducing an electric current into molten metal in an endless refractory channel encircling the magnetic core, and causing molten metal to extend through an upright channel and pass out thru another similar upright channel leading from another part of the endless channel, said upright channels being of sufficient height to maintain a head of metal causing increased static pressure on` the metal in the endless channel during induction heating thereof.

0. An electric induction furnace comprising a magnetic core and a metal shell attached to said core in such manner that the laminations of the core together with the metal shell form the container for the refractory lining, said refractory lining forming an endless channel around one leg of said magnetic core.

7.` In'an electric induction furnace comprising a magnetic core around one leg of which is an endless channel in refractory material, the combination of a part of the magnetic core and shell sections connected with said part of the magnetic core to form together the container for the refractory lining materiali 8. An electric induction furnace comprising an endless pipe interlcoping the magnetic core, said endless pipe having* refractory material within the same with an endless channel to contain molten metal to form the secondary circuit, and a branch pipe having refractory material and a channel communicating with said first-named channel and leading upwardly to contain molten metal and increase the static pressure on the molten metal in said first-named channel.

' 9. In an electric furnace, the combination with a primary circuit, of refractory material having an endless channel Vtherein lying in an approximately horizontal plane to contain molten metal and form the secondary circuit, and additional refractory material having therein a channel leadingv upwardly from said first-named channel to receive molten metal and in* crease the static pressure in said first-named channel whereby large currents may be induced through a comparatively small amount of metal in the secondary circuit.

10. In an electric furnace, the combination with a primary circ'uit, of an endless channel in a horizontal plane in refractory material to contain molten metal to form the secondary circuit, an auxiliary channel leading upwardly from such horizontal channel, a spout for pouring the molten metal from said horizontal channel, and an additional spout for pouring the molten metal from said upright channel.

11. In an electric furnace, the combination with a primary circuit, of an endless channel in refractory material to'contain molten metal to form the secondary circuit, and a plurality of spaced-apart upwardly extending channels in refractory material to receive molten metal and increase the static pressure on the molten metal in the secondary circuit to permit the latter to have induced therein comparatively large currents.

12. In an electric induction furnace, the combination with a plurality of removable sections of an endless casing, each section being adapted to receive refractory material with a channel therein communicating with the channels of the other sections to form an vendless channel for receiving molten metal to form thesecondary circuit, a magnetic core interlooping such secondary circuit, and means for increasing the static pressure on the molten metal during the operation of the electric furnace.

13. In an electric induction furnace, the combination with an endless casing containing refractory materialy with an endless channel therein adapted to contain molten metal to form the secondary circuit, a magnetic core interlooping such secondary circuit, and spaced-apart upwardly extending pipes of refractory material communicating with said endless channel to receive molten metal and increase the static pressure 0n the molten metal in said channel while comparatively large currents are being induced in such secondary circuit.

14. In an electric induction furnace the combination of a plurality of channels each forming a closed secondary circuit around a magnetic core and means for passing molten metal into one channel and out another whereby the metal passes thru more than one channel in series with each other.

15. An electric induction furnace for continuously heating molten metal while the molten metal passes thru the channels of said furnace, said furnace comprising a channel in refractory material encircling a magnetic core, a vertically extending entrance gate for metal to enter and another vertically extending exit gate in another part of said furnace whereby metal may enter and pass thru said heating channel during heating thereof and meantime an increased static pressure can be maintained on the metal in the secondary `induction circuit by means of the head of metal in the exit gate.

16. The process of passing metal continuously thru a furnace which consists in pouring` it into an upwardly extending channel connecting with a channel in which the metal may be heated by current induced therein and causing the metal to flow out from another upwardly extending channel from said channel in which the metal is heated inductively thereby causing increased metal head on the portion of the molten metal which is heated inductively.

17. In an electric induction furnace for the heating of molten metal while passing therethru, the combination with an induction heating channei encircling a magnetic core of two or more upwardly extending wells for intake and outflow of molten metal to increase the static pressure on the metal being heated.

18. In an electric induction furnace using small channels in refractory material, the combination of a detachable metal shell container for refractory material, a channel for molten metal within said channel formllO Mmmm

ing a part me a single tum secondary www former circuiz, and means of attaching, mici containei to im induction furnace,

19. An electric induction famme com prising a plurality of verticaiiy amending chambers connected ai: mail' imm? mmxis by two or more i'eiatiwiy "minds in liefmemry mateiai @m mams @if iw dancing @mmm im @he msai im siii@ chmmei by means of mgmic omsencimiimg pass one, he mhh/i.

lim Witness Wiie-ao if hereunto subsciibe my mime ibis 6th @my @if February, A., D. 15

E E. GREENE. 

